Wello simply clips around a smartphone – in this case an iPhone – with contacts to place your fingers on to make a reading.

The case connects to your smartphone using Bluetooth, making it compatible with a range of devices, including the iPhone and many Android smartphones and tablets.

Azoi, the company behind Wello, has managed to shrink the technology behind a range of medical devices that are normally the size of printers down to the size of a credit card.

In miniaturising the technology, Azoi has also reduced its power requirements to levels that can be powered by a small battery and give weeks of battery life, rather than requiring constant power from the mains. Photograph: Samuel Gibbs/The GuardianWello is very easy to use. Placing your fingers on the contacts creates a circuit through your body for measuring your heartbeat and other bioelectric functions. It is important to keep your fingers from touching as well as your legs and feet to avoid short circuiting the measurements. Photograph: Samuel Gibbs/The GuardianThe contacts on the top link with contacts on the back of the case to complete the circuit. Photograph: Samuel Gibbs/The GuardianThe user has to hold the case and not move or speak for around 10 seconds. The demonstration unit took an average reading over 30 seconds so that movement and speech could be isolated from the readings.

Wello presents a user’s vital statistics, including heart rate, blood oxygen levels and blood pressure as an easy to read set of numbers and graphs, charting daily, weekly and monthly readings. Photograph: Samuel Gibbs/The GuardianThe collated data allows users to spot abnormalities or changes in their heart and lung function and get help if needed. The data can also be shared with a medical professional, giving doctors a patient’s baseline readings and allowing far better personalised diagnosis.

“Everyone is different,” said Hamish Patel chief executive of Azoi speaking to the Guardian. “One person’s normal level can be another person’s abnormal level and it is very difficult to know without a baseline reading.” Photograph: Samuel Gibbs/The GuardianPatel said that a user’s data was kept secure and private on the device and not uploaded to the cloud unless the user chooses to share their data with other parties or services.

Azoi is also working on integrating data from other wearable devices including fitness trackers, with Fitbit currently on-board and others to be added before Wello’s release in the summer, providing a wealth of collated data for the quantified self.

The ECG readout shows your heart beat over time, allowing early warning signs of heart problems or other medical conditions to be spotted, either by a human or algorithmically by the Wello software. Photograph: Samuel Gibbs/The GuardianThe back of the Wello case sports the two finger contact pads. Photograph: Samuel Gibbs/The GuardianThe current Wello case resembles a thin iPhone case, providing protection from scratches and minor impacts while adding the health monitoring functions. Photograph: Samuel Gibbs/The GuardianThe top finger contacts are clearly marked by slightly raised pads on the side edge of the case. Photograph: Samuel Gibbs/The GuardianThe Wello case is thin and light, adding very little in the way of bulk to the iPhone. Photograph: Samuel Gibbs/The GuardianThe electronic components of Wello are housed in a small card, which will slot into a suitable phone case. As Wello connects via Bluetooth to the smartphone, a variety of models will be supported by bespoke cases, including Android phones.

When a user changes their phone it they will simply take the Wello card out and slot it into a new case. Photograph: Samuel Gibbs/The GuardianThe heart of Wello is this thin card, which fits into a smartphone case to provide the finger contacts to measure a user’s vitals.

Lung function can also be measured using a small add-on spirograph accessory, which clips onto the side of the smartphone case using magnets. Users simply blow through the tube, as they would a similar device at the doctors to give a reading of lung volume and health.

Wello is available for pre-order for the iPhone 4S or newer, as well as for Android, for £120 shipping in the summer. Photograph: Samuel Gibbs/The Guardian